Diode laser (808 nm) applied to oral soft tissue lesions: a retrospective study to assess histopathological diagnosis and evaluate physical damage

Diode laser surgery for the treatment of denture-induced fibrous hyperplasia: a case report

Denture-induced fibrous hyperplasia (DIFH) is a persistent lesion caused by low-intensity chronic injury of the tissue in contact with an ill-fitting, over-extended denture. This fibrous connective tissue lesion commonly occurs in oral mucosa in patients showing important alveolar ridge atrophy. Surgical excision is the treatment of choice for DIFH. This article describes a successful laser surgery to remove a DIFH on a lower alveolar ridge of a patient wearing an ill-fitting completely removable denture. The use of a diode laser may result in less surgical time, less bleeding during surgery, more vestibular depth, better re-epithelialization of the wound, and no need for suturing.

Deep learning-assisted 3D laser steering using an optofluidic laser scanner

Laser ablation is an effective treatment modality. However, current laser scanners suffer from laser defocusing when scanning targets at different depths in a 3D surgical scene. This study proposes a deep learning-assisted 3D laser steering strategy for minimally invasive surgery that eliminates laser defocusing, increases working distance, and extends scanning range. An optofluidic laser scanner is developed to conduct 3D laser steering. The optofluidic laser scanner has no mechanical moving components, enabling miniature size, lightweight, and low driving voltage. A deep learning-based monocular depth estimation method provides real-time target depth estimation so that the focal length of the laser scanner can be adjusted for laser focusing. Simulations and experiments indicate that the proposed method can significantly increase the working distance and maintain laser focusing while performing 2D laser steering, demonstrating the potential for application in minimally invasive surgery.

Accident due to Incorrect Selection of Diode Laser Technique in the Treatment of Oral Venous Malformation

Venous malformation (VM) originates from a congenital venous network disorder, configuring about 40% of the vascular anomalies that occur in the head and neck region. The usage of diode lasers in the treatment of VM is associated with various advantages, such as short operating time and few postoperative complications. Nevertheless, for larger and deeper VM treatment, it may require more than one session for the complete resolution of the lesion. Laser surgery for oral VM may induce heat accumulation due to excessive irradiation causing adverse events postoperatively, including pain and ulcer formation with scarring. In this clinical case, it was recommended to use the leopard technique (LT) to reduce the lesion size, evaluate the remaining unhealed lesion, and apply different laser techniques to obtain the complete resolution of the lesion.

Tissue response to different incision tools in animal model

PURPOSE

The aim of this study is to compare the repair of incisions performed with microdissection electrocautery tip, conventional electrocautery tip, high potency diode laser, and conventional scalpel blade in a in vivo model.

METHODS

Different incisions were performed in adults Holtzman rats using the four types of instruments: microdissection electrocautery tip, conventional electrocautery tip, high potency diode laser, and conventional scalpel blade, in different periods of healing process. Thirty rats were divided into 5 groups, according to the period of euthanasia-24 h, 48 h, 72 h, 7 days, and 14 days. All animals received four incisions, each by a different method. Quantitative histological and histomorphometric analyses were performed using hematoxylin and eosin (HE) and Picrosirius Red staining.

RESULTS

Inflammatory profile and tissue repair presented small statistically significance differences comparing conventional scalpel blade and microdissection tip; moreover, both presented quantitatively superior to the others.

CONCLUSION

It is believed that the microdissection tip can perform a dynamic incision just as a common scalpel blade, but more effective. Furthermore, it can promote a better hemostatic control of the surgical field that is comparable to conventional electrocautery tip without affecting tissue repair.

Histological implications of high-power laser use in the oral soft tissue lesions: a systematic review

The objective of this study was to describe the histological artifacts caused by high-power laser use compared to cold scalpel surgery in oral soft tissue lesions. Clinical studies that evaluated and compared histological artifacts resulting from the use of high-power lasers and cold scalpels in oral soft tissue lesions biopsies were retrieved from seven databases and four grey literatures, up to July 2022. The risk of bias was investigated using the ROBINS-I tool. The certainty of the evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation approach. Seven studies were eligible for qualitative analysis. Based on the results obtained, those four studies had a low risk of bias, and three studies had an unclear risk of bias. The certainty of the evidence was classified as low. Limited evidence showed that epithelial artifacts such as loss of intraepithelial and subepithelial adhesions, accompanied by pyknotic, fusiform, and/or hyperchromic nuclei, were more common when a high-power laser device was used. Four articles reported that the use of high-power lasers did not interfere with the histopathological diagnosis of oral soft tissue lesions. Due to the heterogeneity of the data, a meta-analysis was not performed. Compared to the use of cold scalpels, histological artifacts, particularly those observed in epithelial tissue, are more common when high-powered lasers are used in oral lesions biopsies. The eligibility criteria and adequate indications of high-power lasers in different oral soft tissue lesion treatments must be respected to avoid tissue artifacts that impair precise histopathological diagnosis.

Management of oral leukoplakia with an 808-nm high-power diode laser: a single-center experience

PURPOSE

High-power diode laser emerges as a promising approach to the treatment of oral leukoplakia (OL); however, its short- and long-term effects have been barely explored. This study evaluated the postoperative endpoints and the recurrence rate of high-power diode laser treatment in a well-defined series of patients with OL.

METHODS

A prospective analysis was performed on 22 individuals comprising 31 OL. The lesions were irradiated using the following protocol: Indium-Gallium-Arsenide diode laser, 808 nm, continuous-wave mode, 1.5-2.0 W, 780.0 ± 225.1 J, and 477.1 ± 131.8 s. Postoperative pain was assessed with a visual analog scale at three endpoints. Clinical follow-up was performed on all patients and the Kaplan-Meier test was used to analyze the probability of recurrence.

RESULTS

The series consisted mostly of women (72.7%) with a mean age of 62.8 years. A single laser session was performed in 77.4% of cases. The median score on the scale that assessed pain on the 1st, 14th and 42nd postoperative day was 4, 1, and 0, respectively. The mean follow-up period per lesion was 28.6 months (range: 2-53 months). A complete response was observed in 93.5% of OL cases, while 6.5% had recurrence. The probability of recurrence at 39 months was 6.7%. No patient experienced malignant transformation.

CONCLUSION

High-power diode laser for the treatment of OL is safe and effective during the trans- and postoperative period. These findings represent an alternative approach to the management of OL, mainly because a low recurrence rate was observed.

The Impact of Laser Thermal Effect on Histological Evaluation of Oral Soft Tissue Biopsy: Systematic Review

The aim of the study is to review the literature to observe studies that evaluate the extent of the thermal effect of different laser wavelengths on the histological evaluation of oral soft tissue biopsies. An electronic search for published studies was performed on the PubMed and Scopus databases between July 2020 and November 2022. After the selection process, all the included studies were subjected to quality assessment and data extraction processes. A total of 28 studies met the eligibility criteria. The most studied laser was the carbon dioxide (CO₂) laser, followed by the diode laser 940 nm-980 nm. Six studies were focused on each of the Erbium-doped Yttrium Aluminium Garnet (Er:YAG), Neodymium-doped Yttrium Aluminum Garnet (Nd:YAG) lasers, and diode lasers of 808 nm and 445 nm. Three studies were for the Potassium Titanyl Phosphate (KTP) laser, and four studies were for the Erbium, Chromium-doped Yttrium, Scandium, Gallium, and Garnet (Er,Cr:YSGG) laser. The quality and bias assessment revealed that almost all the animal studies were at a low risk of bias (RoB) in the considered domains of the used assessment tool except the allocation concealment domain in the selection bias and the blinding domain in the performance bias, where these domains were awarded an unclear or high score in almost all the included animal studies. For clinical studies, the range of the total RoB score in the comparative studies was 14 to 23, while in the non-comparative studies, it was 11 to 15. Almost all the studies concluded that the thermal effect of different laser wavelengths did not hinder the histological diagnosis. This literature review showed some observations. The thermal effect occurred with different wavelengths and parameters and what should be done is to minimize it by better adjusting the laser parameters. The extension of margins during the collection of laser oral biopsies and the use of laser only in non-suspicious lesions are recommended because of the difficulty of the histopathologist to assess the extension and grade of dysplasia at the surgical margins. The comparison of the thermal effect between different studies was impossible due to the presence of methodological heterogeneity.

Thermal damage and excision time of micro and super pulsed diode lasers: A comparative ex vivo analysis

OBJECTIVES

The primary aim of this ex vivo study was to evaluate thermal damage and cutting efficiency of micro and super pulsed diode lasers. The secondary aim was to suggest a guideline to perform simple surgical excisions adequate for histopathological evaluation.

MATERIAL AND METHODS

Ten groups of 10 specimens of pig tongues were excised using a blade (G1), a micro pulsed (G2-G9), and a super pulsed diode (G10) lasers. Different output power, pulse duration, pulse interval, and duty cycle were tested. Quantitative measures of thermal damage and excision times were recorded. Statistical analysis was performed at a significance level of 5%.

RESULTS

The control group (G1) presented no thermal damage. Within the laser groups (G2-G10), no statistically significant differences in depth of thermal damage (µm) were noted. G3 showed significantly less area of thermal damage (mm² ) when compared with G7 and G9 (p < .05). The median excision time of the control group and super pulsed diode laser group were significantly lower (p < .001) than the micro pulsed diode laser groups.

CONCLUSIONS

The cutting efficiency of the super pulsed diode laser is comparable to traditional blade, and with appropriate parameters, these lasers can produce predictable surgical outcomes with less collateral damage.

A histological evaluation of the mice oral mucosal tissue wounds excised with diode laser, Er:YAG laser, and cold scalpel

Laser has been considered to show many favorable characteristics, including wound healing acceleration, hemostasis, biostimulation, and microbial inhibition. Previous studies have investigated the effect of laser treatment during the process of wound healing, with conflicting results. To date, there is still no unified conclusion on the effect and application principle of clinical laser therapy. This study evaluated the incision morphology, wound healing speed, and histological changes in mice oral mucosal wounds excised with diode laser, Er:YAG laser, and cold scalpel. The results showed that compared with the cold scalpel group, laser treatments caused more tissue thermal damage and carbonization, which led to a healing delay. However, lasers also showed some advantages, including hemostasis, regular incision, and immune response mobilization, suggesting that lasers may be beneficial in some specific cases, such as reducing intraoperative accidents and wound tissue laceration and controlling bleeding and postoperative infection. This study provides a theoretical basis for clarifying the effect of laser treatments and their clinical application principle.

Diode laser photocoagulation of intraoral (and perioral) venous malformations: Cases series

Vascular anomalies are subdivided into vascular tumors (hemangiomas) and vascular malformations. They are frequently located in the head, neck, and oral cavity. They are common complaints reported in patients seeking treatment for aesthetic or functional issues. However, recent advances in the diagnosis and management of these lesions are improving treatment strategies. This review provides both basic and up-to-date knowledge on the most common vascular anomalies encountered by practitioners. Due to the wide variability of treatment options which often generates debate, this paper work aims to provide a comprehensive approach of these lesions based upon current concepts and practical clinical experience. Our article is about 4 patients who had consulted for one or several purplish, elevated, well limited and soft lesion. These lesions was not painful, but worrying for patients. Therapies for VAs continue to generate a dilemma for oral surgeons. Several treatment options were reported, including conventional surgery with or without adjunctive preoperative embolization, and drug therapies, such corticosteroids, intralesional injection of corticosteroids and intralesional injections of sclerosing agents. All of these therapeutic approaches carry a high risk of severe side effects such as scars, pain, and bleeding [7]. Nowadays, advances in the use of lasers have allowed doctors an effective treatment with minimal side effects [9]. All our cases described in this article were done by Pr Haitami, using the 980 nm Diode laser, and a complete healing was observed in about 8 months at the most. The laser is therefore a great help in the management of this type of lesion.

Efficacy of Diode Laser in Treating Oral Papilloma: A Case Report

Background:

Oral squamous papilloma is the most common lesion caused by the Human Papillomavirus (HPV). They are benign proliferation, often painless, and with cauliflower or verrucous appearance.

Objective:

The aim of this report is to describe a clinical case of oral squamous papilloma and its treatment with a high-intensity diode laser.

Case Presentation:

A 65-year-old female patient sought care at the Special Laboratory of Lasers in Dentistry (LELO), University of São Paulo, Brazil, complaining of growth of a soft tissue mass in the jugal mucosa. Based on these clinical characteristics and history, Papilloma was the initial clinical diagnosis of the lesion. Although the lesion was small in size, measuring approximately 0.5 cm, the diagnostic method used was biopsy, and for treatment, a high-intensity diode laser at a wavelength of 980 nm was used.

Conclusion:

It can be concluded that Laser Therapy can be used by dental clinicians to treat these kinds of oral lesions and should be considered as an effective alternative to conventional surgery.

Histological Ex Vivo Evaluation of the Suitability of a 976 nm Diode Laser in Oral Soft Tissue Biopsies

INTRODUCTION

Laser-induced thermal effects can preclude a safe histological evaluation of biopsy resection margins. The aim of this study was to evaluate the suitability of a 976 nm diode laser in oral soft tissue biopsies in an ex vivo study.

MATERIALS AND METHODS

A 976 nm diode laser (Solase®, Lazon Medical Laser, China) has been used in the contact mode, using a 400 μm fiber tip, at different parameters from 4 to 6 W in the continuous wave (CW), with a fluence between 3184 and 4777 J/cm2, and pulsed wave (PW) mode, with a fluence between 318,4 and 477,7 J/cm2, to obtain 30 samples from fresh pig cadaver tongues. All specimens were subdivided into 6 groups (from A to F), and each group consisted of 5 samples. Two sections were obtained from each sample. A histological analysis was performed using an optical microscope at magnifications of 5x and 10x. Statistical analysis was carried out using Kruskal-Wallis and Dunn's tests.

RESULTS

The results showed that histological readability was optimal in all the samples. The thermal damage was negligible in all groups. The average thermal damage was 208.40 ± 133.81 μm in the epithelial tissue and 330.14 ± 147.45 μm in the connective tissue. The statistical analysis showed no differences between the groups (p > 0.05).

CONCLUSION

A 976 nm diode laser demonstrated good surgical effectiveness that provoked little peripheral damage in the cut edges and allowed a safe histological diagnosis. Clinical Relevance. In oral pathology, many times, there is fear in using the laser to remove some lesions due to its thermal effect on the tissues close to the lesion. This effect is always present in the use of the laser, but the intent is to minimize this effect to have as little alteration as possible on the surrounding tissues.

Quantitative determination of cut efficiency during soft tissue surgery using diode lasers in the wavelength range between 400 and 1500 nm

Within the scope of this ex vivo study, the cut efficiency was investigated with eight diode laser wavelengths in the range from 400 to 1500 nm. Incisions on porcine gingiva samples were generated in CW-mode at a power range of 0.5–4 W using a bare fiber (∅ = 320 μm) in contact and non-contact mode at a cut speed of 2 mm/s. Cut depths, cut widths, and thermal damages were recorded based on histological sections and were evaluated via measurement masks. Moreover, with respect to the controllability of a therapeutic measure, an efficiency factor was defined. At powers above 2 W, for 445 nm, the maximum cut depth was 820 μm and 344 μm for 810 nm, respectively. At all wavelength and power ranges, the cut width averaged 125 μm. At minimum output power (0.5 W), the spatial expansion of the thermal damage in the tissue surface layer corresponds in the blue/green wavelength range from the very beginning of the laser impact to the fiber core diameter. It could be shown that increases in the diode laser power output do not correlate to the same extent with the incision depth nor with thermal damage to tissue.

The Integration of a Dual-Wavelength Super Pulsed Diode Laser for Consistent Tissue Ablation in the Esthetic Zone: A Case Series

Introduction

A diode laser is one of the universally compact accepted laser systems used fundamentally for soft tissue applications. Most diode laser devices have a single wavelength of either 810 nm for superior coagulation or 980 nm for tissue ablation. In these case series, the use of dual wavelengths (810 nm and 980 nm) in combination with super pulsing has provided a cleaner cut (no charring) with faster healing that eases the placement of the final restoration in the esthetic zone. Case Description. The present case series describe four cases in the esthetic zone that achieved hemostasis ablation without collateral damage to enhance gingival balance of definitive restoration. The gingivoplasty and gingivectomy modes are used to achieve efficient tissue ablation. Although there is no specific mode indicated in the FDA laser requirement for gingival depigmentation, the procedure could be safely performed with the dual-wavelength diode laser.

Result

All four patients revealed a good esthetic outcome and reported no pain postoperatively. Healing was uneventful, and definitive restoration was delivered within two to four weeks postoperatively.

Conclusion

Within the limitation of these case series, the dual-wavelength super pulsed diode laser has the capacity to deliver peak powers resulting in efficient cutting and less tissue charring and also as an alternative tool for removal of gingival pigmentation. Prospective clinical research with larger sample size is needed for conclusive results.

An Overview of Diode Laser-Assisted Oral Surgery

Among all lasers with generally accepted surgical capabilities, the diode laser is most commonly used for the surgical removal of proliferating lesions and the photocoagulation of venous malformations of the oral cavity. The laser provides several advantages for clinicians, including an absence of intraoperative bleeding and no need for stitches. The laser benefits patients because it reduces postoperative edema and pain, with fast mucosal restoration during healing by second intention. We report a case series to highlight the capabilities of the diode laser in oral surgery procedures along with our suggestions.

Diode laser surgery versus electrocautery in the treatment of inflammatory fibrous hyperplasia: a randomized double-blind clinical trial

OBJECTIVES

To compare the efficacy and safety of diode laser and electrocautery techniques for inflammatory fibrous hyperplasia (IFH) removal.

MATERIALS AND METHODS

In this randomized double-blind clinical trial, 40 individuals were randomly allocated to two groups: group 1 (G1) consisted of 20 individuals assigned to treatment with diode laser and group 2 (G2) consisted of 20 individuals assigned to treatment with electrocautery. The following transoperative parameters were evaluated: bleeding, temperature, and surgical technique parameters (energy deposited on tissue, flow rate, and time of incision). The postoperative parameters evaluated were as follows: pain, functional alterations (chewing, speaking), analgesic medication intake, swelling, healing of the wound area, and patient satisfaction.

RESULTS

Among the 40 individuals included in the study, four (two in G1 and two in G2) did not complete the entire follow-up. Therefore, 36 individuals (18 in G1 and 18 in G2) participated. Participants in G1 and in G2 had similar demographic characteristics. No difference regarding the trans- or postoperative parameters evaluated was observed between G1 and G2 (p > 0.05). Also, no difference regarding the time for healing was observed between groups.

CONCLUSIONS

Diode laser seems to be as effective and safe as electrocautery when applied under similar conditions for IFH removal.

CLINICAL RELEVANCE

IFH corresponds to 65% of the lesions observed in denture wearers. This study shows that under similar conditions diode laser is as effective and safe as electrocautery for removal of IFH.

Histological Effects of an Innovative 445 Nm Blue Laser During Oral Soft Tissue Biopsy

Continuously evolving laser devices can be used in various fields; they are an alternative to the traditional cold blade surgery to perform biopsies of oral soft tissues. The aspect focused on in this paper is the possibility to use the 445 nm diode laser (Eltech K-Laser srl, Treviso, Italy) in complete safety, by evaluating its thermal effects during microscopy. A histological evaluation of the alteration of the peri-incisional edges on 10 samples was realized. All excisional biopsies were related to clinically unsuspected lesions and performed by the same expert operator. The surgical procedure was performed with the same laser parameters and the same pathologist evaluated the thermal effect on the samples. An average value of the detected tissue alteration was calculated; the average damage of the epithelium was 650.93 μm, while in the connective tissue it was 468.07 μm. In all the cases a clear diagnosis was possible, and no clinical complications were observed; so, the 445 nm diode laser proved to be a device that can be safely used for biopsies of clinically unsuspicious lesions. Due to the small number of cases, this in vivo preliminary experience needs to be extended.

Diode Laser Excision of Blandin-Nuhn Mucocele

The glands of Blandin and Nuhn are mixed mucous and serous glands that are embedded within the musculature of the anterior tongue ventrum. The differential diagnosis for lesions in that area is often challenging and includes other salivary and nonsalivary lesions. This affects decision-making, surgical management, and measures to prevent complications. Unlike conventional cold blade surgery, diode laser use may simplify such treatment.

Clinical Outcomes of Diode Laser Treatment of Ankyloglossia in Children and Young Adults: A Report of Two Cases

Lingual frenectomy/frenotomy is a relatively safe procedure for removing the lingual frenulum when it is thick, very tight, and/or restricting tongue movements, especially in children. Among all treatment options, diode laser surgery is the most effective. We present two cases wherein diode laser surgery was safe, with a near-total absence of intraoperative bleeding.

Diode Laser Photocoagulation of Oral Venous Malformations in Patients on Anticoagulant Therapy Without Drug Discontinuation

The diode laser is widely used for the treatment of venous malformations of the oral cavity nowadays. Anticoagulant therapy is usually modified or suspended in patients needing oral surgery, especially for vascular lesion treatment. We report a case series of venous malformations in patients on anticoagulant therapy treated by diode laser photocoagulation without drug discontinuation.

Comparison of diode laser - Oral tissue interaction to different wavelengths. In vitro study of porcine periodontal pockets and oral mucosa

Background

The aim of this in vitro study was to evaluate the effect of diode lasers at different wavelengths and power settings in handmade incisions in periodontal pockets and in oral mucosa of porcine tissue considering thermal damage, necrosis and the affected area of the soft tissue.

Material and Methods

Combining the following laser wavelengths, 445nm, 532nm (KTP), 810nm, 980nm, 1064nm and 1470nm, and a power range from 0.5W to 2.0W in a continuous wave mode (CW), we made handmade incisions in porcine periodontal pockets and oral mucosa. After histological processing, we measured the area of ​​lost tissue, the area of ​​thermal damage and the area of ​​necrosis. Then, we performed ANOVA to evaluate the difference between groups and two-way ANOVA to identify the influence of the laser-type variables and the power on the results.

Results

We applied an ANOVA test to evaluate the results, where statistical analysis showed clear differences between the 1470nm and 810nm laser groups that refer to thermal damage and necrosis in the periodontal pocket surface. Regarding the oral mucosa surface, the 1064nm laser showed differences in the analysis of lost tissue. According to the applied power, all the variables we studied (lost tissue area, area of thermal damage and necrosis) showed higher values when using a power of 2.0W instead of 0.5W.

Conclusions

According to our results, the 810nm diode laser for oral soft-tissue biopsy using power ranges between 0.5W and 2W would be the best choice to avoid thermal damage in peri-incisional margins.

Key words:Laser surgery, soft tissue, diode laser, KTP laser, thermal damage, necrosis.

Early tongue carcinomas (clinical stage I and II): echo-guided three-dimensional diode laser mini-invasive surgery with evaluation of histological prognostic parameters. A study of 85 cases with prolonged follow-up

The management of patients with early stage (cT1-T2) tongue squamous cell carcinoma without clinicoradiologic evidence of neck node metastasis (cN0) has been widely debated over the last 3 decades and still remains controversial. Nevertheless, the identification of patients with low-stage tumours at high-risk for occult cervical metastases is imperative before planning treatments of primary tumours, as well as that of prognostic markers which may possibly select those patients who may benefit of additional workup after surgery in view of the high metastatic potential of the primary tumour. The pre-surgical evaluation of tongue malignant primary tumour (for assessing lateral and deep margins) along with diode laser surgery (with accurate incision, bleeding-free and with reduced/absent post-surgical complications) may lead to a more conservative but equally decisive surgical treatment, also with a greater patient compliance. We studied 85 consecutive cases of cT1-T2 N0 tongue squamous cell carcinoma who had been managed by the following diagnostic/therapeutic protocol: pre-operative high definition ultrasound examination for the evaluation of size and depth, followed by three-dimensional surgical excision by diode laser (wavelength of 800 ± 10 nm, output power of 8 W in continuous wave, flexible optic fibre of 320 μm in contact mode) and detailed histological analyses of well-established prognostic parameters (tumour grade, thickness, depth, front of infiltration and surgical margins) with statistical analysis. No post-surgical photobiomodulation was performed. Overall, 58.82% of patients were stage I, 18% stage II, and the most frequent histotype was squamous cell carcinoma (97.64%). Large nests invasion pattern was observed in 64 cases, expansive pattern in 9, invasion in single cells in 12; front of invasion involved the muscle in 62 cases, vessels in 6, nerves in 15; peritumoural vascular invasion was assessed in 6 patients and perineural invasion in 15. Selective neck lymphadenectomy was performed in 9 cases, and clinically occult node metastases were detected in two cases. At follow-up, 78 patients (98.73%) were alive and free of disease, one patient experienced tumour-related death, while the remaining 6 died for non-disease-related causes. All the histological prognostic parameters were statistically significant (χ² test; p = 0.05), thus leading to a prognostic weight classification with a three-tiered stratification. On the bases of these results, the authors maintain that the reported diagnostic/therapeutic protocol, including the pre-operative echo-guided three-dimensional evaluation, the following diode laser mini-invasive surgery for tumour excision and the histological examination along with the proposed three-tiered stratification of histological prognostic parameters may allow proper management of clinical stage I and II early tongue carcinomas.

Diode Laser Photocoagulation of Intraoral and Perioral Venous Malformations After Tridimensional Staging by High Definition Ultrasonography

Objective: To determine optimal settings for use of diode lasers to treat vascular malformations in the head and neck. Background: Diode lasers are generally accepted as effective tools to treat vascular malformations in the head and neck, yet there are no standardized treatment protocols for this treatment approach. Settings for these lasers, in addition to laser type and size and lesion depth are important variables for designing appropriate treatments for vascular malformations. Materials and methods: Vascular venous malformations (VeMs) were classified into five groups according to high-definition ultrasound measurements of superficial dimensions (<1, 1-3, and >3 cm) and lesion extension depth (≤5, and >5 mm). Using a 800 ± 10 nm diode laser for surgical procedures, we treated lesions by two different approaches: trans-mucous/cutaneous photocoagulation (8 and 12 W pulsed wave for cutaneous and mucosal lesions, respectively) and intralesional photocoagulation using a laser set to 13 W in the pulsed wave modality to treat both cutaneous and mucosal lesions. Results: We treated 158 vascular VeMs. According to preoperative staging, there were 52 lesions in Group A (superficial dimension <1 cm), 28 in Group B₁ (superficial dimension from 1 to 3 cm, extension depth ≤5 mm), 16 in Group B₂ (superficial dimension from 1 to 3 cm, extension depth >5 mm), 42 in Group C₁ (superficial dimension >3 cm, extension depth ≤5 mm), and 12 in Group C₂ (superficial dimension >3 cm, extension depth >5 mm). All Group A lesions showed complete healing after a single laser treatment, whereas 7%, 10%, 12%, and 16% of lesions classified in Groups B₁, B₂, C₁, and C₂, respectively, required further treatments. Conclusions: The laser settings defined in this study were associated with a reduced number of laser applications needed for effective treatment of vascular VeMs. Moreover, the cooling of irradiated tissues, together with prolonged application of a topical regenerative gel, provided good treatment acceptability, reduced the number of postoperative complications, and promoted faster healing of covering tissues.

Efficacy and safety of diode laser during circumvestibular incision for Le Fort I osteotomy in orthognathic surgery: a triple-blind randomized clinical trial

The aim of this triple-blind randomized clinical trial was to evaluate the efficacy and safety of diode laser during circumvestibular incisions for Le Fort I osteotomy in orthognathic surgeries in comparison with conventional techniques using electrocautery and scalpel. Patients were randomly allocated to one of three groups based on the technique employed to perform incisions: diode laser, electrocautery, and scalpel. The parameters used to evaluate the efficacy and safety of diode laser were incision velocity, duration of surgery, bleeding rate, alterations in postoperative functions, pain, edema, wound clinical healing, and infection. Thirty patients were enrolled in the study (10 per group). Regarding bleeding, the incisions performed with diode laser promoted a lower bleeding rate compared with scalpel and electrocautery (p = 0.00). The diode surgical laser was effective during the incision procedure, but required a longer time to perform the incisions compared with the other techniques evaluated (p < 0.05). No statistically significant difference was detected between groups regarding total surgical time or other safety parameters (p > 0.05). Thus, diode laser proved to be effective and safer during circumvestibular incisions for Le Fort I osteotomy than conventional devices.

A histological evaluation of the surgical margins from human oral fibrous-epithelial lesions excised with CO2 laser, Diode laser, Er:YAG laser, Nd:YAG laser, electrosurgical scalpel and cold scalpel

Background

We aim to evaluate the presence of histological artefacts in the surgical margins of human oral fibro-epithelial hyperplasias excised with lasers of different wavelengths, and also electrosurgical scalpel and cold scalpel. Moreover, we aim to determine if some of these instruments could impair the normal histological diagnosis of these lesions.

Material and Methods

We included 130 consecutive surgical samples of 80 females and 50 males (mean age of 53.82±16.55) with a histological diagnosis of an oral benign fibrous-epithelial hyperplasias. The samples were categorized into 6 groups according to the type of instrument used: CO2 laser group, diode laser group, Er:YAG laser group, Nd:YAG laser group, electrosurgical scalpel group and cold scalpel group. Histological instrument-induced changes were microscopic evaluated and related with clinical and pathological variables.

Results

The instrument with highest tissue damage extension (TDE) was the electrosurgical scalpel (1002.2µm±434.92), followed by diode laser (913.73 µm±322.45), Nd:YAG (899.83µm±327.75), CO2 laser (538.37µm±170.50), Er:YAG laser (166.47µm±123.85), and at last with fewer alterations the cold scalpel group (2.36µm±7.27) (P< 0.001). The most regular incision was observed in CO2 laser group, followed by Er:YAG laser, Nd:YAG laser, electrosurgical scalpel and diode laser group with the less regular incision using cold scalpel as comparison (P< 0.001). A correlation was found between the incision score and TDE (P< 0.001). Regarding histological diagnosis, no case showed any limitation of diagnosis related with the use of any instrument evaluated.

Conclusions

Our results suggest that lasers can be used for the excision of oral benign fibrous-epithelial hyperplasias, without hispathological diagnosis limitations, as long as the physical properties of each laser are known and respected. Er:YAG laser have shown to be a laser with few tissue damage extension and with good incision regularity, been a possible instrument of choice for the surgical removal of these lesions.

Key words:CO2 laser, diode laser, Er:YAG laser, Nd:YAG laser, oral mucosa.

Temperature and depth evaluation of the in vitro effects of femtosecond laser on oral soft tissue, with or without air-cooling

Femtosecond laser is an effective and safe tool in many surgeries, but the studies of its effect on oral soft tissue ablation are insufficient. This study aimed to investigate the effect of soft tissue ablation with a 1030-nm femtosecond laser on temperature and depth. Twenty Sprague-Dawley rat tongue specimens were obtained and flat-mounted. The 1030-nm femtosecond laser was controlled by a computer system, with a set distance of 4.7 mm between the laser aperture and soft tissue surfaces. Ten specimens were ablated for > 1 min with or without air-cooling for temperature measurement, while the other 10 specimens were ablated for depth measurements, using the following parameters: (i) 3 W, 2000 mm/s; (ii) 3 W, 4000 mm/s; (iii) 5 W, 2000 mm/s; (iv) 5 W, 4000 mm/s; (v) 8 W, 2000 mm/s; (vi) 8 W, 4000 mm/s. Temperature changes were measured using a type-K thermocouple. The depth attained using different power and scanning speed settings was measured by a three-dimensional morphology measurement laser microscope. Laser power, scanning speed, and air-cooling effects were determined. Higher energy and lower speed induced higher temperatures (p < 0.05), which were significantly decreased by air-cooling (p < 0.05). The lowest ablation depth was obtained at 3 W and 4000 mm/s (72.63 ± 6.47 μm) (p < 0.05). The greatest incision depth was achieved at 8 W and 2000 mm/s (696.19 ± 35.37 μm), or 4000 mm/s (681.16 ± 55.65 μm) (p < 0.05). The 1030-nm femtosecond laser application demonstrates clinically acceptable ablation efficiency, without marked temperature damage, in a controlled manner.

Treating Mucocele in Pediatric Patients Using a Diode Laser: Three Case Reports

A mucocele is the most common minor salivary gland disease and among the most common biopsied oral lesions in pediatric patients. Clinically, a mucocele appears as a round well-circumscribed painless swelling ranging from deep blue to mucosa alike in color. Mucoceles rarely resolve on their own and surgical removal under local anesthesia is required in most cases. Different treatment options are described in the literature, including cryosurgery, intra-lesion injection of corticosteroid, micro-marsupialization and conventional surgical removal using a scalpel, and laser ablation. Therefore, the goal of this paper was to report three cases of mucocele removal in pediatric patients using a diode laser with a one-month follow-up. Mucoceles were removed by a pediatric dentist using a diode laser with a wavelength of 930 nm in continuous mode and a power setting of 1.8 Watts. In all cases, no bleeding occurred during or after the procedure and there was no need for suturing. On clinical examination during the one-month follow-up, in all three cases there was minimal or no scarring, minimal post-operative discomfort or pain, and no recurrence. Diode lasers provide an effective, rapid, simple, bloodless and well accepted procedure for treating mucocele in pediatric patients. Minimal post-operative discomfort and scarring was reported by all the three patients.

Prospective study of the 532 nm laser (KTP) versus diode laser 980 nm in the resection of hyperplastic lesions of the oral cavity

Background

The aim of this study is to evaluate the resection of hyperplastic lesions on the buccal mucosa comparing the 532nm laser (KTP), versus diode 980nm laser, considering pain, scarring, inflammation and drug consumption that occurred postoperatively with each lasers.

Material and Methods

A prospective study of consecutive series of 20 patients in two groups that presents hyperplastic lesions on the buccal mucosa. The choice of the KTP laser or diode 980nm laser for the surgery was made randomly. The power used was 1.5W in both groups in a continuous wave mode with a 320 μm optical fiber. Parameters of pain, scarring, inflammation and consumption of drugs were recorded by a Numerical Rating Scale and evaluated postoperatively. These recordings were made the day of the surgery, 24 hours after, 14 and 28 days after.

Results

Pain and inflammation was light - moderate. The consumption of paracetamol was somewhat higher in the diode 980nm laser versus the KTP laser after 24 hours, although data was not statistically significant; significant differences were found after 28 days in regards to pain (p = 0.023) and inflammation (p = 0.023), but always in the absence parameter so we find no pain in both lasers. Scarring in the two types of laser showed no differences along the visits, with not detected scar retractable.

Conclusions

Although there is a slight histological difference regarding the KTP laser in the oral soft tissues for clinical use, both wavelengths are very suitable for excision of oral fibroma.

Key words:Laser surgery, Laser therapy, oral surgery, soft tissue, 980 nm diode laser, 532 nm KTP laser.

High-power diode laser in the circumvestibular incision for Le Fort I osteotomy in orthognathic surgery: a prospective case series study

The incisions during orthognathic surgery are classically performed with conventional scalpel or electrocautery. Considering that the high-power diode laser surgery may provide advantages when compared to conventional incision techniques, the current study aimed to present a prospective case series of patients submitted to circumvestibular incision for Le Fort I osteotomy. Ten patients with dentofacial deformities who underwent to rapid assisted maxillary expansion or bimaxillary orthognathic surgery were enrolled in the study. All incisions were performed by a single surgeon using an 808-nm diode laser, with an optical fiber of 600 μm, at a power of 2.5 W, in a continuous-wave mode. The performance of the incision was evaluated by incision velocity, bleeding, edema, secondary infection, clinical healing, and pain. The velocity of the incision ranged from 0.10 to 0.20 mm/s (mean 0.13 ± 0.03 mm/s). Considering bleeding during the soft tissue incision, all surgeries were classified as absent bleeding. All patients presented a clinical healing of the surgical wound in a period that range from 3 to 5 weeks and experienced swelling during the follow-up period. On average, approximately 50% of the swelling had resolved after the third postoperative week, and 28.8% of swelling remained after 2 months after the surgery. The pain decreased after 2 and 3 days, and 90.0% of the patients reported no pain after 7 postoperative days. High-power diode laser is effective and safety during circumvestibular incisions for Le Fort I osteotomy in orthognathic surgery decreasing bleeding, surgery time, pain, and edema after orthognathic surgery.

Laser Surgery of Soft Tissue in Orthodontics: Review of the Clinical Trials

Introduction: Recently, a wide variety of procedures have been done by laser application in orthodontics. Apart from the mentioned range of various treatments, laser has become a tool for many soft tissue surgeries as an alternative to conventional scalpel-based technique during orthodontic treatments in the management of soft tissue. Due to scarce information in the latter subject, this study was designed in order to include clinical trials that included soft tissue ablation by laser in orthodontics. Methods: Literature was searched based on PubMed and Google Scholar databases in 5 years (2010-2015) with English language restriction and clinical trial design. Studies that performed soft tissue application of laser during orthodontic treatment were extracted by the authors. Results: Only eight studies met the inclusion criteria. No significant difference was found between laser ablation and conventional scalpel technique in the matter of treatment outcome. However, few issues remained to clarify the differences in the mentioned procedures. Conclusion: Laser performance can be recommended in case of preceding less bleeding and discomfort during surgical procedure. There are still quandaries among clinical application of scalpel-based surgery in aesthetic region with bracket-bonded teeth. Precaution and knowledge regarding the characteristics of laser beam such as wavelength, frequency, power and timing is extremely needed.

Effects of freezing, fixation and dehydration on surface roughness properties of porcine left anterior descending coronary arteries

BACKGROUND

To allow measurements of surface roughness to be made of coronary arteries using various imaging techniques, chemical processing, such as fixation and dehydration, is commonly used. Standard protocols suggest storing fresh biological tissue at -40°C. The aim of this study was to quantify the changes caused by freezing and chemical processing to the surface roughness measurements of coronary arteries, and to determine whether correction factors are needed for surface roughness measurements of coronary arteries following chemical processes typically used before imaging these arteries.

METHODS

Porcine left anterior descending coronary arteries were dissected ex vivo. Surface roughness was then calculated following three-dimensional reconstruction of surface images obtained using an optical microscope. Surface roughness was measured before and after a freeze cycle to assess changes during freezing, after chemical fixation, and again after dehydration, to determine changes during these steps of chemical processing.

RESULTS

No significant difference was caused due to the freeze cycle (p>0.05). There was no significant difference in the longitudinally measured surface roughness (Ra_L=0.99±0.39μm; p>0.05) of coronary arteries following fixation and dehydration either. However, the circumferentially measured surface roughness increased significantly following a combined method of processing (Ra_C=1.36±0.40, compared 1.98±0.27μm, respectively; p<0.05). A correction factor can compensate for the change Ra_Cβ=Ra_C1+0.46in Ra_C due to processing of tissue, Where Ra_Cβ, the corrected Ra_C, had a mean of 1.31±0.21μm.

CONCLUSIONS

Independently, freezing, fixation and dehydration do not alter the surface roughness of coronary arteries. Combined, however, fixation and dehydration significantly increase the circumferential, but not longitudinal, surface roughness of coronary arteries.

Management of Oral Lichen Planus by 980 nm Diode Laser

Introduction: Oral lichen planus (OLP) is a mucocutaneous disease with uncertain etiology. As the etiology is unknown standard treatment modalities are not available. The traditional and common treatment relies on corticosteroids whether topical or systemic. In recent years, development of lasers made a proper path to use this instrument for treatment of the diseases which are refractory to conventional treatments. Previous studies in this field used CO2, ND:YAG, Excimer and some wavelength of diode lasers for the treatment of different types of lichen planus. Case Report: In this study, we present an OLP case which is treated using 980 nm diode laser. The result was measured by visual analogue scale (VAS) and clinical assessment; as a result, symptoms including pain and soreness started to decrease within a week, and by the end of a month completely subsided; the lesion disappeared totally as well. No recurrence was observed after a month and no side-effect was reported. Conclusion: 980 nm diode laser can be successfully used for treatment of patients with OLP.

In vitro histological evaluation of the surgical margins made by different laser wavelengths in tongue tissues

BACKGROUND

Lasers have become standard tools for the surgical treatment of oral lesions. The purpose of this study is to determine the surgical margins and histologically evaluate the tissue thermal effects induced by different types of surgical instruments.

MATERIAL AND METHODS

Cuts were made in pork tongues' mucosa with different lasers (Er:YAG at 2W with and without air / water spray and at 4W with and without air / water spray; CO2 at 3.5W and 7W in pulsed mode and at 7W in continuous mode; the diode laser at 3.5W and boost 3.5W in pulsed mode; Nd:YAG at 6W, 40Hz and electroscalpel at 5W and conventional scalpel as control. Macroscopic and microscopic morphological changes were evaluated.

RESULTS

The results of this study showed that the surgical instruments that caused greater tissue damage extension were: the Nd:YAG laser (670.68μm), the diode 3.5W and boost PW (626.82μm), the CO2 7W CW (571.18μm), the CO2 at 7W PW (485.45μm), the diode 3.5W PW (456.15μm), the electroscalpel (409.57μm) and lastly the CO2 laser 3.5W PW (306.19μm) and Er:YAG (74.66μm) laser, regardless of power, mode or air / water spray used. An association between the Tissue Damage Extension and the Degree of Carbonization (r = 0.789; P = 0.01), and an association between the Tissue Damage Extension and Regularity of the Incision were found (r = -, 299; P = 0.01).

CONCLUSIONS

The results of this study suggest that lasers can be used in soft tissues biopsies of the oral cavity, enabling a correct histopathological analysis, as long as the biological effects of each laser type are considered. The Er:YAG laser revealed its potential for biopsies of the oral mucosa ensuring a successful histological evaluation and the CO2 laser at 3,5W in pulsed mode presented itself as the best choice for surgeries with hemostasis. Key words:CO2 laser, diode laser, Er:YAG laser, laser surgery, Nd:YAG laser, oral mucosa, thermal effect.

Evaluation of Temperature and Roughness Alteration of Diode Laser Irradiation of Zirconia and Titanium for Peri-Implantitis Treatment

OBJECTIVE

This study investigated the effects of diode laser (gallium, aluminium, arsenide [GaAlAs]) irradiation with decontamination parameters on the temperature and roughness of yttrium-stabilized tetragonal zirconia polycrystal (Y-TZP), titanium (TI), and sandblasted large grit acid-etched titanium (SLA).

MATERIALS AND METHODS

Three groups (n = 10) of standardized disks with 5 mm diameter and 2 mm thickness were produced with Y-TZP obtained from computer-aided design and computer-aided manufacturing (CAD-CAM), machined TI and SLA. The diode laser single application (808 nm, 20 sec, 1 W, 50 Hz, t on = 100 ms, t off = 100 ms, energy density = 28.29 J/cm(2)) was performed in contact mode, on each disk. The temperature was measured by a thermosensor attached to a digital thermometer fixed to the opposite irradiated surface. The temperature gradient (ΔT) was calculated (ΔT = final temperature - initial temperature) for each group. The parameters Ra (in μm) and Sa (in μm(2)) were measured by white light confocal laser microscopy to express the surface roughness. Data of ΔT was statistically analyzed by one way ANOVA at the 95% confidence level and compared by Tukey post-hoc test (α = 0.05). Roughness data was analyzed by t test.

RESULTS

The diode laser irradiation presented the following results (ΔT value): Y-TZP = 10.3°C(B); TI = 38.6°C(A), and SLA = 26.7°C(A). The ΔT values ((°)C) of the titanium groups were higher than for the Y-TZP group. For both roughness parameters (Ra and Sa), data did not show statistical significant differences to "irradiation" factor (p > 0.05) to Y-TZP and SLA. The Ra results (in μm) were: Y-TZP (control) = 0.73 (0.55); Y-TZP (irradiated) = 0.45 (0.27); SLA (control) = 0.74 (0.23); and SLA (irradiated) = 0.99 (0.33). The Sa results (in μm(2)) were: Y-TZP (control) = 1.39 (1.05); Y-TZP (irradiated) = 0.73 (0.41); SLA (control) = 0.85 (0.08); and SLA (irradiated) = 1.27 (0.44).

CONCLUSIONS

Diode laser irradiation for peri-implantitis treatment increased both zirconia and TI temperature without surface roughness alterations.

Neurofibromas of the Oral Cavity: Clinical Aspects, Treatment, and Outcome

OBJECTIVE

This study aimed to evaluate the efficacy of diode laser for the surgical treatment of neurofibromas (NF), in terms of clinical outcome and therapeutic success.

BACKGROUND DATA

The NF is a benign tumor of the peripheral nerve sheath, characterized by the proliferation of Schwann cells, perineural cells, and endoneural fibroblasts. NF may occur as a solitary lesion, or as part of a generalized neurofibromatosis syndrome; much more rarely it occurs in the form of multiple neurofibromas with no associated syndrome. Two distinct variants of neurofibromatosis have been described: types I and II.

METHODS

Ten cases are reported (6 women and 4 men, age range 43-70 years) with smooth, painful, or painless lesions of the oral mucosa. Lesions were completely excised using a diode laser at 980 nm wavelength, average power 2.0 W, in continuous wave mode, with 320 μm optical fibers, for 45 sec average time.

RESULTS

Complete healing occurred within 20 days. There were no adverse effects; patients were carefully followed up and there have been no recurrences after an interval of 3 months to 3 years.

CONCLUSIONS

The results of this diode laser treatment of NF demonstrate good effectiveness of this novel therapy, which may replace conventional surgical procedures.

Diode Laser Excision of Oral Benign Lesions

INTRODUCTION

Lasers have made tremendous progress in the field of dentistry and have turned out to be crucial in oral surgery as collateral approach for soft tissue surgery. This rapid progress can be attributed to the fact that lasers allow efficient execution of soft tissue procedures with excellent hemostasis and field visibility. When matched to scalpel, electrocautery or high frequency devices, lasers offer maximum postoperative patient comfort.

METHODS

Four patients agreed to undergo surgical removal of benign lesions of the oral cavity. 810 nm diode lasers were used in continuous wave mode for excisional biopsy. The specimens were sent for histopathological examination and patients were assessed on intraoperative and postoperative complications.

RESULTS

Diode laser surgery was rapid, bloodless and well accepted by patients and led to complete resolution of the lesions. The excised specimen proved adequate for histopathological examination. Hemostasis was achieved immediately after the procedure with minimal postoperative problems, discomfort and scarring.

CONCLUSION

We conclude that diode lasers are rapidly becoming the standard of care in contemporary dental practice and can be employed in procedures requiring excisional biopsy of oral soft tissue lesions with minimal problems in histopathological diagnosis.

Pseudoepitheliomatous hyperplasia after diode laser oral surgery. An experimental study

Background

To examine the process of epithelial reparation in a surgical wound caused by diode laser.

Material and Methods

An experimental study with 27 Sprage-Dawley rats was undertaken. The animals were randomly allocated to two experimental groups, whose individuals underwent glossectomy by means of a diode laser at different wattages, and a control group treated using a number 15 scalpel blade. The animals were slaughtered at the 2nd, 7th, and 14th day after glossectomy. The specimens were independently studied by two pathologists (blinded for the specimens’ group).

Results

At the 7th day, re-epithelisation was slightly faster for the control group (conventional scalpel) (p=0.011). At the 14th day, complete re-epithelization was observed for all groups. The experimental groups displayed a pseudoepitheliomatous hyperplasia.

Conclusions

It is concluded that, considering the limitations of this kind of experimental studies, early re-epithelisation occurs slightly faster when a conventional scalpel is used for incision, although re-epithelisation is completed in two weeks no matter the instrument used. In addition, pseudoepitheliomatous hyperplasia is a potential event after oral mucosa surgery with diode laser. Knowledge about this phenomenon (not previously described) may prevent diagnostic mistakes and inadequate treatment approaches, particularly when dealing with potentially malignant oral lesions.

Key words:Diode laser, animal model, oral biopsy, oral cancer, oral precancer, pseudoepitheliomatous hyperplasia.

Biopsy of different oral soft tissues lesions by KTP and diode laser: histological evaluation

Introduction. Oral biopsy aims to obtain clear and safe diagnosis; it can be performed by scalpel or laser. The controversy in this latter application is the thermal alteration due to tissue heating. The aim of this study is the histological evaluation of margins of “in vivo” biopsies collected by diode and KTP lasers. Material and Methods. 17 oral benign lesions biopsies were made by diode 808 nm (SOL, DenMatItalia, Italy) and KTP 532 nm (SmartLite, DEKA, Italy). Samples were observed at OM LEICA DM 2000; margin alterations were evaluated through Leica Application Suite 3.4. Results. Epithelial and connective damages were assessed for each pathology with an average of 0.245 mm and a standard deviation of ±0.162 mm in mucoceles, 0.382 mm ± 0.149 mm in fibromas, 0.336 mm ± 0.106 mm in hyperkeratosis, 0.473 mm ± 0.105 mm in squamous hyperplasia, 0.182 mm in giant cell granuloma, and 0.149 mm in melanotic macula. Discussion. The histologic aspect of lesions influenced the response to laser, whereas the greater inflammation and cellularity were linked with the higher thermal signs. Many artifacts were also associated to histologic procedures. Conclusion. Both tested lasers permitted sure histologic diagnosis. However, it is suggested to enlarge biopsies of about 0.5 mm, to avoid thermal alterations, especially in inflammatory lesions like oral lichen planus.

Gingiva laser welding: preliminary study on an ex vivo porcine model

OBJECTIVE

The use of lasers to fuse different tissues has been studied for 50 years. As none of these experiments concerned the oral soft tissues, our objective was to assess the feasibility of laser gingiva welding.

MATERIALS AND METHODS

Porcine full-thickness gingival flaps served to prepare calibrated samples in the middle of which a 2 cm long incision was closed, either by conventional suture or by laser tissue welding (LTW). To determine the irradiation conditions yielding the best tensile strength, 13 output power values, from 0.5 to 5 W, delivered either at 10 Hz or in continuous wave mode, were tested on six indocyanine green (ICG) concentrations, from 8% to 13% (588 samples). Then, some samples served to compare the tensile strength between the laser welded and the sutured gingiva; the other samples were histologically processed in order to evaluate the thermal damage extent. The temperature rise during the LTW was measured by thermocouples. Another group of 12 samples was used to measure the temperature elevation by thermal camera.

RESULTS

In the laser welding groups, the best tensile strength (p<0.05) was yielded by the 9% ICG saline solution (117 mM) at 4.5 W, 10 Hz, and a fluence of 31.3 kJ/cm(2). The apposition strength revealed no statistically significant difference (p<0.05) between the sutured and the laser welded gingiva at 4.5 W, 10 Hz, and 9% ICG solution. The mean temperature was 74±5.4°C at the upper surface and 42±8.9°C at the lower surface. The damaged zone averaged 333 μm at the upper surface.

CONCLUSIONS

The 808 nm diode laser associated with ICG can achieve oral mucosa LTW, which is conceivable as a promising technique of gingival repair.

Laser-induced osteoblast proliferation is mediated by ROS production

Low-level laser therapy (LLLT) is widely used in regenerative medicine and in dental therapy by virtue of its beneficial effects in a plethora of pathological conditions. In this study, the effect of a 980 nm diode laser on pre-osteoblasts proliferation has been evaluated, along with reactive oxygen species (ROS) production. We hypothesized that ROS were a key factor in LLLT-induced pre-osteoblasts proliferation, as it is known that ROS can induce the activation of many biological pathways, leading to cell proliferation, differentiation or apoptosis. Murine pre-osteoblasts MC3T3 cells were irradiated with different energy outputs (1-50 J) in the absence or presence of the antioxidant N-Acetyl-L-cysteine (NAC). Laser treatment, in the absence of NAC, was able to induce a fluence-dependent statistically significant increase in ROS generation, while the presence of NAC strongly inhibited it. Cell proliferation, measured after laser stimulation, was significantly increased both at low and higher energy, with a peak at 10 J in the absence of the antioxidant. On the contrary, in the presence of NAC, laser irradiation was not able to induce any cell proliferation, suggesting a crucial role of ROS in this laser-induced cell effect. These results suggest that LLLT may be a useful tool for bone regeneration therapy and an effective range of fluences to be used is indicated.

Clinical and surgical management of odontoma

OBJECTIVE AND BACKGROUND

Odontomas are hamartomatous developmental malformations of the dental tissues. We present a retrospective study of recent clinical experience using erbium-doped yttrium aluminum garnet (Er:YAG) (wavelength 2940 nm) and chromium-doped yttrium scandium gallium garnet lasers (Er,Cr:YSSG) (wavelength 2780 nm) for the surgical treatment of these lesions, and score postsurgical pain.

MATERIALS AND METHODS

This retrospective study comprised 35 odontomas treated at the Department of Oral Pathology and Laser-Assisted Surgery, San Martino Hospital, University of Genoa, Italy. Of 35 Caucasian patients (23 male, 12 female; ages 8-35; odontomas localized at various oral subsites) those in Group 1 (n=25) had odontomas excised by laser (Er:YAG laser operating at 2940 nm, pulse width 100 msec, curved handpiece, truncated cone HPX tip, 400 μm with energy output 250-400 mJ per pulse, frequency 15 Hz; and Er, Cr: YSGG laser, power 3.5 W, frequency 20 Hz, 55% air/45% water spray, H (hard tissue) mode, pulse width 190-750 μsec variable). In Group 2 (n=10) odontomas were excised by conventional surgery. Pain was assessed using a visual analog scale (VAS). Clinical outcome was determined at 6-12 months.

RESULTS

Complete responses were achieved in 100% of the laser-treated odontomas, which compares favorably with reported results of conventional surgery. A statistically significant difference in VAS score was found between patients treated with traditional scalpel surgery (median=4.00) and those who underwent laser surgery (median=3.00).

CONCLUSIONS

In treating odontomas, a laser surgery protocol effectively minimizes pain, maintains an excellent clinical outcome, and requires minimal additional treatment time compared with conventional surgery.

Human papilloma virus lesions of the oral cavity: healing and relapse after treatment with 810-980 nm diode laser

This study evaluated the therapeutic efficacy of laser therapy in treating oral human papilloma virus (HPV) lesions. In particular, mode of action, healing, postoperative patient compliance, visual numeric scale (VNS) pain index, and recurrence were analyzed. During 2001-2012, in 170 patients (80 women and 90 men), 174 intraoral and lip HPV lesions were detected and excised by diode laser of different wavelengths (810-980 nm), with an average power of 2.1 W, in continuous wave mode, using 300 to 320 μm optical fibers. In most cases (95.4%), complete healing occurred in the first 30 days. There were no adverse effects and all patients were carefully followed up until complete healing occurred, documenting any complications. There was only one recurrence, which was later treated successfully; the mean VNS pain score was below one. In treating HPV lesions, the diode laser is not only a valuable tool for their eradication but especially it reduces relapses, thanks to the characteristics of the laser light.

The influence of water/air cooling on collateral tissue damage using a diode laser with an innovative pulse design (micropulsed mode)-an in vitro study

Since the diode laser is a good compromise for the daily use in dental offices, finding usage in numerous dental indications (e.g., surgery, periodontics, and endodontics), the minimization of the collateral damage in laser surgery is important to improve the therapeutical outcome. The aim of this study was to investigate the effect of water/air cooling on the collateral thermal soft tissue damage of 980-nm diode laser incisions. A total of 36 mechanically executed laser cuts in pork liver were made with a 980-nm diode laser in micropulsed mode with three different settings of water/air cooling and examined by histological assessment to determine the area and size of carbonization, necrosis, and reversible tissue damage as well as incision depth and width. In our study, clearly the incision depth increased significantly under water/air cooling (270.9 versus 502.3 μm-test group 3) without significant changes of incision width. In test group 2, the total area of damage was significantly smaller than in the control group (in this group, the incision depth increases by 65 %). In test group 3, the total area of damage was significantly higher (incision depth increased by 85 %), but the bigger part of it represented a reversible tissue alteration leaving the amount of irreversible damage almost the same as in the control group. This first pilot study clearly shows that water/air cooling in vitro has an effect on collateral tissue damage. Further studies will have to verify, if the reduced collateral damage we have proved in this study can lead to accelerated wound healing. Reduction of collateral thermal damage after diode laser incisions is clinically relevant for promoted wound healing.